In a head, a center vertical cross section passing through a face center satisfies the following (a) and (b): (a) when a boundary point between an inner surface of a crown portion and an inner surface of a face portion is defined as a CF inner surface boundary point, a curvature radius of a head inner surface at the CF inner surface boundary point is 6.0 mm or greater and 10.0 mm or less, and the head thickness at the CF inner surface boundary point is 2.0 mm or greater; and
(b) when a spot located 10 mm apart from the CF inner surface boundary point toward the crown side is defined as a spot C10, the head thickness reduces gradually from the CF inner surface boundary point to the spot C10, and the head thickness at the spot C10 is 1.0 mm or less.

Disclosed herein is a casting cluster for casting a body of a golf club head made of titanium or a titanium alloy. The casting cluster comprises a receptor and a plurality of runners coupled to the receptor and configured to receive molten metal from the receptor. The casting cluster also includes at least twenty-eight main gates. At least two of the main gates are coupled to each of the runners and each main gate is configured to receive molten metal from a corresponding one of the plurality of runners. The casting cluster further comprises at least twenty-eight molds. Each mold of the at least twenty-eight molds is configured to receive molten metal from a corresponding one of the main gates and to cast a body of a golf club head that has a volume of at least 100 cm.sup.3.

Methods of manufacturing a golf club head comprising one or more stiffening members proximate the face, and particularly solid rods or a plate with one or more cutouts, is disclosed herein. One method comprises the steps of preparing a wax mold of a golf club head including a plate stiffening member with excess material, casting the golf club head, and machining away the excess material. Another method comprises the steps of casting a golf club body, providing a plate stiffening member, providing a face component such as a face cup, tack welding the plate stiffening member and the face component to the golf club body, and welding these parts together.

Golf club heads with ribs are described herein. A golf club head comprises a first rib protruding from an interior surface of the club head, and a second rib protruding from the interior surface of the club head. The first rib comprises a first axis and the second rib comprises a second axis; wherein the first and second rib axes intersect each other forward the front end of the club head body. The club head further comprises a first side rib protruding from the interior surface of the heel end, and a second side rib protruding from the interior surface of the toe end. The first side rib and the second side rib generally extend in a front end to rear end direction, and can be linear or curvilinear. The ribs provide structural support and sound control for the club head.

Described herein are embodiments of golf club heads with slits and flexure inserts. The slit comprises an opening through the club head body communicating between the exterior of the club head and the hollow interior cavity. The flexure insert can comprise a spring component and a cap. The spring component creates a spring effect within the flexure insert that increases the internal energy of the club head at impact, leading to improvements in ball speed and other golf ball performance characteristics.

A golf club head includes: a body including: a striking face having a lower leading edge and an opposite upper topline edge, and a sole extending rearward from the lower leading edge, wherein the striking face and the sole form at least part of an outer surface of the body; a weight chamber formed in the outer surface; and a weight including a heavy portion and a light portion, being positionable in the weight chamber with a first orientation, and being positionable in the weight chamber with a second orientation that is rotated from the first orientation about a first axis.

Disclosed herein is a golf club head comprising at least one crown opening and at least one crown insert attached to the body and covering the at least one crown opening. The golf club head further comprises at least one sole opening and at least one sole insert attached to the body and covering the at least one sole opening. The golf club head additionally includes at least one weight member configured to clamp first and second ledges at selected locations along a sliding weight track. The golf club head also comprise a coefficient of restitution (COR) feature located on the sole of the golf club head. The at least one crown insert is formed from a composite material having a density between 1 g/cc and 2 g/cc. The at least one sole insert is formed from a composite material having a density between 1 g/cc and 2 g/cc.

Golf club heads are described herein, and in one embodiment including a body with an exterior surface defining a first body volume of at least about 400 cm.sup.3. The body has a bottom portion, a top portion, a front portion, and a back portion. A face positioned at the front portion of the body and is configured to receive an impact. A top portion silhouette profile located along a perimeter of the top portion is further described. The top portion silhouette profile defines the outer bounds of the top portion in an X-direction and Y-direction. At least one indentation can be located on the bottom portion below the crown silhouette profile. The removal of the at least one indentation from the bottom portion can create a second body volume that is at least 12 cm.sup.3 larger than the first body volume.

A golf club head that is capable improving on the inertia properties of a golf club head all while also improving the Center of Gravity (CG) location is disclosed herein. More specifically, the golf club head in accordance with the present invention achieves a relative low Moment of Inertia (MOI) about the Z-axis (MOI-Z) as well as a relatively low MOI about the Shaft-axis (MOI-SA), all combined with a high MOI about the X and Y-axis (MOI-X and MOI-Y) and maintaining a consistently and relatively low CG location measured along a direction tangent to the hosel axis along the X-Y plane (CG-B).

A golf club head that is capable improving on the inertia properties of a golf club head all while also improving the Center of Gravity (CG) location is disclosed herein. More specifically, the golf club head in accordance with the present invention achieves a relative low Moment of Inertia (MOI) about the Z-axis (MOI-Z) as well as a relatively low MOI about the Shaft-axis (MOI-SA).